Reference

Estimating tropospheric lifetimes and ozone-depletion potentials of one- and two-carbon hydrofluorocarbons and hydrochlorofluorocarbons

Estimating tropospheric lifetimes and ozone-depletion potentials of one- and two-carbon hydrofluorocarbons and hydrochlorofluorocarbons. Nimitz, Jonathan S.; Skaggs, Stephanie R. (New Mexico Eng. Res. Inst., Univ. New Mexico, Albuquerque, NM 87131-1376, USA). Environ. 354-21-2 and 338-64-7 are also occured in this study. Sci. Technol., 26(4), 739-44 (English) 1992. CODEN: ESTHAG. ISSN: 0013-936X. DOCUMENT TYPE: Journal CA Section: 59 (Air Pollution and Industrial Hygiene) Section cross-reference(s): 53 Tropospheric lifetimes and O3-depletion potentials (ODPs) are estd. for all 53 possible 1- and 2-C hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs). The relationships among C-H bond strength, activation energy for removal of H by OH, tropospheric lifetime, and ODP are examd. Algorithms are developed that are easy to apply and accurate enough for initial screening purposes. On the basis of extant theory and anal., the controlling variables for detg. HCFC tropospheric lifetimes include no. of H atoms, mol. wt., no. of C atoms, no. of Cl atoms a and b to H, and no. of F atoms b to H. The formula presented predicts lifetimes for mols. with atm. lifetimes below 30 yr with a root mean square (rms) error of a factor of 2.4. An algorithm is also presented to calc. ODP based on tropospheric lifetime; the overall rms error for calcg. ODP from the structure is a factor of 2.5. In many cases, ODPs of Cl-contg. compds. are predicted to be below 0.001. These ests. also aid in making tentative choices among alternative HFCs and HCFCs based on environmental considerations. .